Question

Read the following statements (1 - 3) related food chain and select the correct statement/s ?

1. Food chains have multiple paths interconnecting plants and animals.
2. Grazing food chain begins with the degradation of organic matter.
3. In aquatic ecosystems, the grazing food chain accounts for major conduits of the energy flow.

• A. 1 only
• B. 2 only
• C. 1 and 3 only
• D. 3 only

Answer 1

The correct option is D 3 only

Food chain is a chronological series of organisms each depending on others for food. It shows a linear path of transmission of food or energy from one trophic level to the other. As in the food chain, a higher trophic level organism feeds on a specific organism of lower trophic level. Hence statement 1 is incorrect.

A network of interconnected food chains in a community of different organisms forms a food web. It is the food web which shows the multiple paths or networks in which flow of energy occurs. Hence in the food web, a higher trophic level organism contains access to a more number of lower trophic level organisms.


Food chains are of two types : grazing food chain and detritus food chain.

In the detritus food chain, the dead organic matter (detritus) is the starting point. The organisms like decomposers or saprotrophs which are mainly fungi and bacteria meet their energy and nutrient requirements by degrading detritus.

In the grazing food chain, the starting point is at the producers or autotrophs. The primary consumers consume these producers, the secondary producers in turn consume the primary producers and so on. Hence statement 2 is incorrect.

In aquatic ecosystems, it is the grazing food chain that accounts for the major conduit of the energy as the decomposition is very less here. In terrestrial ecosystems, it is the detritus food chain that accounts for major conduit of the energy flow. Hence statement 3 is correct.